PAT (PvE Auto Tuner) is a system designed to help us balance all generic PvE content in the module. It's driven by database entries and utilizes NWNX to modify various statistics of existing creatures and/or create PAT-configured creatures according to a predefined set of roles, skills and feat selections.
Instead of applying Challenge Ratings only to individual creatures, PAT allows us to instead define Challenge Ratings for Areas and/or creatures. If a creature that has no set individual PAT CR is spawned in an area that has a PAT CR defined, the creature gets reconfigured by PAT to be of the CR the area requires.
You can find a list of currently assigned area CRs here: List of Area CRs